--> Plate Tectonic Model for the Early Opening of the Gulf of Mexico

2020 AAPG Hedberg Conference:
Geology and Hydrocarbon Potential of the Circum-Gulf of Mexico Pre-salt Section

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Plate Tectonic Model for the Early Opening of the Gulf of Mexico

Abstract

The Late Paleozoic-Early Mesozoic tectonic evolution of Mexico and the Gulf of Mexico (GOM) is a polemic topic because data is scarce. However, paleogeographic maps based in surface geology, key outcrops, well data, and geophysical data indicate that a regional continuous transgression from the Pacific occurred since the Late Triassic, forming extensive shallow water shelves associated with a continuous western subduction volcanic arc. The breakup and dispersion of Pangea in the Late Triassic caused the development of a series of regional grabens and horsts bounded by large recurrent faults which had different displacements through time. This tectonic framework allowed the transgression of Pacific water over extensive areas all along the Pacific coast of Pangea, but marine water did not reach the GOM area until the Bajocian-Bathonian, through the Portal del Balsas Seaway (López Ramos, 1974), and flooded the entire GOM by the Callovian. The Callovian-Early Kimmeridgian sea floor spreading in the GOM, displaced the Yucatan Block (YB) southward ~1300 km, along the Tamaulipas-Oaxaca Transform Fault System, with a counterclockwise rotation of ~39°. These tectonic conditions favored the deposit of the two extensive, salt masses present in this basin. By the Kimmeridgian the GOM was completely open and the YB reached its actual position. An important consideration is that neither the North Atlantic Ocean nor the Caribbean Ocean did not were open before the salt deposition.